Circuit breaker with spring operating mechanism



19, 1955 J. P. ELLSWORTH ETAL 3,213,249-

CIRCUIT BREAKER WITH SPRING OPERATING MECHANISM Filed Aug. 2, 1961 2 Sheets-Sheet 1 5| ON 1/ OFF f 53 37 35 Fig l A, 73 27 83 L I 4 3| i 55 2| 33 67 43 I 2523 B l 63 5| ON OFF r 37 I 53 Fig. 2 7| n O ASH {D O 3 '8 "r9 e5 63 as 59 WITNESSES INVENTORS J P. EH th 8 2 {MI/Q 5222 H2112;

ATTORNEY 1965 J. P. ELLSWORTH ETAL 3,213,249

CIRCUIT BREAKER WITH SPRING OPERATING MECHANISM 2 Sheets-Sheet 2 Filed Aug. 2. 1961 4 g F l 3 3 l 9 7 2 7 5 7| 5 37 7 52 6 6 J 9 F 6 567 8 4 M O 4 5 u w W a W Q G T B i II 9 5/ 8 i 5w 5 HH I U N 3 FE HO O 5 T 2 4 O 8 l 3 7 5 O 98 4 3 2 5 2 United States Patent Office 3,213,249 Patented Oct. 19, 1965 3,213,249 CIRCUIT BREAKER WITH SPRING OPERATING MECHANISM James P. Ellsworth, Beaver, and Robert H. Flick, Brighton Township, Beaver County, Pa, assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a

corporation of Pennsylvania Filed Aug. 2, 1961, Ser. No. 128,763 13 Claims. (Cl. 200-116) This invention relates to circuit breakers and more particularly to manually and automatically operable circuit breakers for controlling lighting and other small or moderate power electric circuits.

An object of this invention is to provide a circuit breaker having improved means for increasing the presence between the contacts of the breaker.

In the patent to M. Bingenheimer, Patent No. 2,624,816, which patent is assigned to the assignee of the instant invention, there is disclosed a circuit breaker having a movable contact arm and spring means biasing the movable contact arm to a closed position. Means are provided for both manual and automatic opening of the circuit breaker.

Another object of this invention is to provide a circuit breaker of the above-mentioned general type with improved means for increasing the contact pressure without increasing the strength of the spring means while maintaining effective manual and automatic operating characteristics.

A more general object of this invention is to provide an improved circuit breaker having increased utility.

Other objects of this invention will be explained fully hereinafter or will be apparent to those skilled in the art.

In the circuit breaker disclosed in theabove-mentioned 'patent, to M Bingenheimer, an overcenter spring is supported under tension between a pivotally supported latched trip member and a movable contact arm that carries a movable contact at one end thereof. The other end of the movable contact arm is operatively connected to a pivotally supported manually operable member. The trip member is latched in a normal position by trip means that operates automatically in response to certain predetermined current values to release the trip member. When released, the trip member, under the force of the tensioned spring, pivots to change the line of action of the spring relative to the centerline of the movable contact arm, whereupon the spring operates to move the movable contact arm to the open position.

In accordance with one embodiment of this invention, the point at which the spring is connected to the trip member is moved to enlarge the angle between the spring and the movable contact arm to thereby increase the component of spring force that effects or maintains contact pressure. In order to maintain effective tripping action, an elongated slot is provided in the trip member and one end of the spring is disposed in the slot so that when the trip member is released, the one end of the spring can move in the slot to an effective operating position wherein the spring force will operate to move the movable contact arm to the open position with a snap action.

In accordance with another embodiment of the invention, the angle between the spring and movable contact arm is enlarged even more than in the first embodiment to further increase the component of spring force that effects contact pressure. The slot in the trip member is lengthened to maintain effective tripping characteristics. In this embodiment, a kicker member is provided to move the upper end of the spring, during manual operation of the breaker, to a more effective operating position.

For a better understanding of the nature and objects of this invention, reference may be had to the following description when taken in conjunction with the accompanying drawings, in which:

FIGURE 1 is a side elevational view, partly in section, of a circuit breaker embodying principles of this invention, the cover plate having been removed to more clearly illustrate the invention, and the circuit breaker mechanism being shown in the closed-circuit position;

FIG. 2 is a view similar to FIG. 1 showing the circuit breaker mechanism in the tripped open position;

FIG. 3 is a transverse sectional view of the circuit breaker taken substantially along the line IIIIII of FIG. 1;

FIG. 4 is a view similar to FIG. 1, of a circuit breaker comprising a different embodiment of the invention, the circuit breaker mechanism being shown in the manually opened or off position;

FIG. 5 is a detail view in elevation illustrating the relative positions of parts of the mechanism of the circuit breaker seen in FIG. 4 when the breaker is in the closed or on position.

FIG. 6 is a partial elevational view, on an enlarged scale with respect to FIGS. 1-4, illustrating another method of attaching the spring to the trip member of the circuit breaker; and

FIG. 7 is a view taken substantially along the line VIIVII of FIG. 6,

Referring to the drawings, and particularly to FIGS. 1-3 thereof, a circuit breaker indicated generally at 3 comprises a housing 11 and a cover plate 13 (FIG. 3), both of molded insulating material, a stationary contact 15, a movable contact 17, an operating mechanism indicated generally at 19, and a strip device indicated generally at 21.

The stationary contact 15 is rigidly secured to the inner end of a terminal member 23 that is seated in an angular slot 15 in the molded housing 11. The outer end of the terminal member 23 is provided with a connecting means 27 for connecting the terminal in an electric circuit. At the opposite end of the housing 11, a terminal 29 is disposed, which terminal 29 supports .a trip device (to be described later) at the inner end thereof. A connector 31 is provided at the outer end of the terminal 29 for connecting the terminal in an electric circuit.

The movable contact 17 is rigidly secured on the lower part of a U-shaped movable contact arm 33 having its upper part or legs (FIG. 3) supported at A in recesses in the legs of a U-shaped operating member 35. The operating member 35 is pivotally supported on a pivot pin 37 that is mounted in a suitable opening in the housing 11 and in a matching opening in the cover 13. An operating spring 39 is connected under tension between the movable contact arm 33 and a releasable carrier or trip member 41 that is pivoted on a pin 43 that is supported in companion openings in the housing 11 and cover 13. The operating spring 39 is attached to the movable contact arm 33 at B by having one end thereof inserted through an opening (FIG. 3) in the movable contact arm. The operating spring 39 is attached to the trip member 41 at C (when the trip memher is in a latched or normal position as shown in FIG. 1) by having the other end thereof inserted in an elongated track or slot 45 (FIG. 1) in the trip member 41. The purpose of having the slot 45 in the trip member 41 will be hereinafter specifically described. Spacers 47 are provided to maintain the trip member 41 properly spaced from the walls of the housing 11 and cover plate 13.

The operating member 35 is provided with an op erating handle 49 molded integral therewith and extending through an opening 51 in the housing 11. The operating lever 35 is also provided with an arcuate portion 53 that cooperates with the housing 11, 13 to substantially close the opening 51. The movable contact arm 33 is electrically connected by means of a flexible conductor 55 to one end of a bimetal element 57 that is a part of the trip device 21. The bimetal element 57 is secured, preferably by welding, to the inner end of the terminal 29.

The movable contact arm 33 is operated manually to open and close the contacts by manipulation of the handle 49. Movement of the handle 49 in a clockwise direction from the full line position shown in FIG. 1 carries the upper part of the movable contact arm 33 to the left (FIG. 1). During the initial part of this opening movement of handle 49 and operating member 35, the movable contact arm 33 is moved downward slightly to additionally charge the tensioned spring 39, and when the parts reach the position where the line of action of the spring 39 is on the left of the center line AB of the movable contact arm 33, the spring discharges sufiiciently to snap the movable contact arm to the open position. The operating handle 49 and movable contact arm 33 are partially shown in the manually open position by dot-and-dash lines in FIG. 1. When the movable contact arm 33 is in the open position, the upper end of the spring 39 remains at the point C in the slot 45.

The contacts are manually closed by reverse operation of the handle 49. counterclockwise movement of the handle 49, and therefore the operating member 35, from the dot-and-dash position (FIG. 1) to the full line position additionally changes the tensioned spring 39 and moves the upper part of the switch arm 33 across to the right of the line of action of the spring 39 whereupon the spring 39 discharges sufliciently to close the contacts with a snap action.

An are extinguisher 59 is provided to quickly eX- tinquish the arc drawn between the contacts 15, 1'7 during the' interruption of the circuit. The are extinguisher may be of any suitable type, the one illustrated comprising a series of slotted plates 61 into which the arc is drawn and broken up into a plurality of serially related arcs that are extinguished in a manner well known in the art.

The circuit breaker 3 is adapted to be tripped open instantaneously, by means of the trip device 21, in response to an overload current above a predetermined value, or a short circuit current. The circuit breaker is adapted also to be tripped open after a time delay in response to a lesser overload current by means of the trip device 21.

The current responsive means or trip device 21 comprises the bimetal element 57 that is connected by means of the flexible conductor 55 to the movable contact arm 33; an electromagnet including two members of magnetic material one of which is a U-shaped core member 63 and the other of which is a movable armature 65; and a latch element 67 that is attached to a resilient member 69 to which the armature 65 is attached. The terminal 29 is secured to the end wall of the casing 11 by means of a screw 71, and the bimetal element 57 is rigidly secured by suitable means, such as welding, to the upper end of the terminal 29. Just below the point of attachment of the bimetal element 57 to the terminal 29, the bimetal element is formed inwardly at right angles and then downwardly for a short distance substantially parallel to the terminal to form a flat surface to which the resilient member 69 is secured. The resilient member 69 is secured to the bimetal element by means of a rivet '73. The lower end of the resilient member 69 is looped as shown at 75, and the upwardly extending end thereof carries an insulating button 77 for insulating the free end of the bimetal 57 from the free end of the resilient member 69. Because of the engagement of the button 77 with the bimetal 57, movement of the bimetal to the right carries the resilient member 69 with it; but movement of the resilient member toward the bimetal is permitted without movement of the bimetal.

The U-shaped core member 63 straddles the bimetal member 57 and is secured thereto preferably by welding. The armature 65 is secured to the resilient member 69 adjacent the core member 63 by means of a rivet 79 that also serves to secure the latch element 67 to the resilient member. The resilient member 69 is normally positioned so that the latch element 67 will engage and restrain the trip member 41 in the operative or normal position shown in FIG. 1. Upon the occurrence of an overload current below a predetermined value of, for instance, 1000% or less of normal rated current, the bimetal element 57 thermally deflects moving its free lower end toward the right (FIG. 1). During this movement, the bimetal element 57, through the insulating button 77, moves the resilient member 69 in the same direction and causes the latch element 67 to release the trip member 41. Upon release of the trip member 41, the spring 39 operates to move the trip member clockwise about its pivot 43 during which motion the upper end of the spring moves longitudinally in the elongated slot 45 from the point C in the one end of the slot to a point D at the other end of the slot. The final motion of the trip member 41 is arrested by engagement of the trip member with a projection 81 that is molded integral with the housing 11. During this motion of the trip member 41 and spring 39, the line of action of the spring 39 is moved to the right of the center line AB of the movable contact arm 33 whereupon the tensioned spring 39 discharges sufiiciently to move the movable contact arm 33 to the open position shown in FIG. 2 with a snap action.

Movement of the movable contact arm 33 to the tripped position moves the operating member 35 clockwise from the full line position shown in FIG. 1. This clockwise movement of the operating member 35 is stopped in an intermediate position (FIG. 2) when a part 82 of the operating member engages a stop pin 83 on the trip member 41. This intermediate position (FIG. 2) of the operating member 35 and handle 49 provides a visual indication that the breaker has tripped.

The circuit breaker is trip-free in that if the handle 49 is held in the on position when the member is released, the spring 39 will still operate to move the movable contact arm 33 to the open position.

Before the contacts can be closed following an automatic opening operation, it is necessary to reset and relatch the mechanism. This is accomplished by moving the handle 49 clockwise (FIG. 2) to the full open or off position during which movement the part 82 of the operating member 35 engages the pin 83 on the trip member 41 to move the trip member counterclockwise about its pivot 43. Near the end of this counterclockwise movement, the free end of the trip member 41 wipes by the latch element 67, to reach the latched position shown in FIG. 1. Thereafter, the movable contact arm 33 is moved to close the contacts 15, 17 in the preveiously described manner by movement of the handle 49 counterclockwise to the closed or on position.

Upon the occurrence of a heavy overload or short circuit or for example more than 1000% of rated current, the current flowing through the bimetal element 57 energizes the core member 63 sufiiciently so that the magnetic flux generated in the core member 63 instantaneously attracts the armature 65 to the core member. This movement moves the resilient member 69 and latch element 67 to the right (FIG. 1) releasing the trip member 41 and effecting instantaneous opening of the contacts in the same manner hereinbefore described with respect to the thermal tripping operation.

In the prior art circuit breaker of the type shown for example in FIG. 1, which prior art type of circuit breaker is disclosed, for example, in the hereinbefore mentioned patent to M. Bingenheimer, Patent No. 2,624,816, the angle between the center lines of the spring 39 and movable contact arm 33 (i.e., the angle corresponding to the angle ABC shown in FIG. 1) was approximately 12". This angle is determined when the circuit breaker is in the closed or on position. By vector analysis, the component of spring force acting to maintain contact pressure between the contacts 15, 17 in this type of structure, is equal to the sine of the above-mentioned angle times the spring force. Thus, in this prior art type of structure, the component of spring force acting to maintain contact pressure is equal to the sine of 12 times the spring force, or .208 times the spring force.

As can be seen in FIG. 1, applicants have increased the angle between the center line L of the spring 39 and the center line AB of the movable contact arm 33 (angle ABC) to approximately 21. In the circuit breaker shown in FIGS. 1-3, therefore, the component of spring force acting to maintain contact pressure when the movable contact arm 33 is in the closed position, is equal to the sine of 21 times the spring force or .358 times the spring force. Thus, without changing the strength of the opening spring, applicants have increased the component of spring force acting to maintain contact pressure to approximately 1.7 times the component of spring force acting to maintain contact pressure in the aforementioned prior-art type of structure.

As shown in FIGS. 1-3, effective tripping characteristics of the circuit breaker are maintained by the provision of the slot-and-pin type of connection between the trip member 41 and the spring 39. During the tripping opera tions, when the trip member 41 is released and falls to the position shown in FIG. 2, the upper end of the spring member 39 slides, under the bias of the spring 39, within the slot 45 to the position D at the other end of the slot, during which motion the line of action of the spring 39 is moved to the right of the center line AB of the movable contact arm 33 to move the contact arm to the open position shown in FIG. 2 with a snap action in the same manner hereinbefore described. Thus, with the provision of the slot-and-pin type of connection between the trip member 41 and spring 39, the angle between the spring 39 and movable contact arm 33 is made large enough to substantially increase contact pressure and during a tripping operation the line of action of the spring 39 is effectively moved to a position wherein the spring operates to open the contacts.

A circuit breaker 3' illustrating a modification of the invention is shown in FIGS. 4 and 5. In this breaker, an elongated track or slot 89 which is longer than the slot 45 shown in FIGS. 1 and 2, is provided in the trip member 41 in order to further increase the angle between the spring 39 and movable contact arm 33 when the breaker is in the closed or on position (FIG. 5). A kicker member 91 is provided for maintaining effective manual operation of the circuit breaker 3' in a manner to be hereinafter specifically described. In all other respects, the circuit breaker 3 is the same as the circuit breaker 3 and, therefore, the reference characters for the other parts of the circuit breaker 3' are the same as the reference characters for the similar parts of the circuit breaker 3.

As shown in FIG. 5, when the circuit breaker 3 is closed, the upper end of the spring 39 is disposed at the point E in one end of the slot 89. This enlarges the angle between the center line L of the spring 39 and the center line AB of the movable contact arm 33 ABE) to 260. Thus, the compoent of spring force acting to maintain contact pressure when the movable contact arm 33 is in the closed position is equal to the sine of 26 times the spring force or .43 84 times the spring force. This is equal to 2.1 times the component of spring force acting to maintain contact pressure in the prior art type of structure shown for example in the aforementioned patent to M. Bingenheimer, Patent No. 2,624,816.

The kicker member 91 is provided to cooperate with the operating member 35 to change the line of action of the overcenter spring 39 during the manual opening operations of the circuit breaker 3. When the handle 49 is rotated clockwise form the on to the otf position, the part 82 of the operating member 35 engages one end 93 of the kicker member 91 rotating the kicker 91 counterclockwise about the pivot 83. During this movement, the other end 95 of the kicker 91 engages the spring 39 moving the upper end of the spring 39 to the right in the slot 89 to the point P. During this movement, the operating lever 35 also moves the upper end of the movable contact arm 33 to the left moving the movable contact arm 33 downward slightly to additionally charge the spring 39. As a result of the movements of both the movable contact arm 33 and the spring 39, the line of action of the spring 39 is moved to the right of the center line AB of the movable contact arm 33 whereupon the spring 39 discharges sufficiently to move the movable contact arm 33 to the open position with a snap action.

During the manual closing operations of the circuit breaker 3, when the handle 49 is moved to the on position, the operating member 35 moves the upper end of the movable contact arm 33 to the right additionally charging the tensioned spring 39 during the initial part of this movement, and, when the movable contact arm 33 reaches a position wherein the line of action of the spring 39 is to the left of the center line AB of the movable contact arm 33, the spring 39 discharges sufiiciently to move the movable arm to the closed position with a snap action. During this movement, the part 82 of the operating lever 35 is moved away from the end 93 of the kicker 91 and the spring 39 moving back to the end E of the slot 89 engages the end 95 of the kicker 91 moving the kicker clockwise about the pivot 83 back'to the position shown in FIG. 5. The end 95 of the kicker 91 moves away from the spring 39 at the end of the closing operation because the kicker 91 falls to the final position shown in FIG. 5 by means of gravity.

Upon the occurrence of either a thermal or an electromagnetic tripping operation, the trip member 41 is released in the same manner hereinbefore described whereupon the trip member 41, under the bias of the spring 39, drops down to the position where it engages the projection 81. During this movement, the upper end of the spring 39 moves to the other end G of the slot 89, and the line of action of the spring 39 is moved to the right of the center line AB of the movable contact arm 33 whereupon the spring 39 operates to move the movable contact arm 33 to the open position with a snap action.

During the tripping operations of the circuit breaker 3', the handle 49 is moved to an intermediate indicating position in the same manner hereinbefore described. After the tripping operations the circuit breakers 3' is reset for manual operation in the same manner hereinbefore described.

For some applications of the circuit breaker 3 (FIGS. 1-3) and/or the circuit breaker 3 (FIGS. 4-5), it may be desirable to reduce the amount of friction between the upper end of the spring member 39 and the trip member 41 so that the spring will more readily move within the associated slot. For these applications, as is shown in FIGS. 6 and 7, a roller 97 may be attached over the spring member 39 which roller will facilitate movement of the upper end of the spring in the associated slot (or 89) during tripping operations of the circuit breaker 3 (FIGS. 1-3), and during both tripping and manual operations of the circuit breaker 3 (FIGS. 4-5).

From the foregoing, it will be understood that there is provided, by this invention, an improved circuit breaker with improved means for increasing the contact pressure without increasing the strength of the operating spring while maintaining effective manual and automatic operating characteristics.

While the invention has been disclosed in accordance with the provisions of the Patent Statutes, it is to be understood that various changes in the structural details thereof may be made without departing from some of the essential features of the invention. It is desired, therefore, that the language of the appended claims be given the broadest reasonable interpretation permissible in the light of the prior art.

We claim as our invention:

1. A circuit breaker comprising, in combination, a stationary contact, a movable contact, a movable contact arm carrying said movable contact and being movable to open and close said contacts, a trip member having a track thereon, a spring structure having one end supported on said movable contact arm and the other end supported on said track, trip means latching said trip member and operating automatically upon the occurrence of overload currents above a predetermined value to release said trip member, said trip member when released moving to effect opening of said contacts, and said spring structure moving between two spaced points on said track to change the line of action of said spring structure during said automatic opening operation.

2. In a circuit breaker, relatively movable contacts, a movable contact arm having one of said contacts secured thereon, a trip member, a spring structure having one end supported on said movable contact arm, slot-and-pin means supporting the other end of said spring structure on said trip member, trip means latching said trip member and operable automatically upon the occurrence of certain abnormal current conditions to release said trip member, said trip member when released moving under the force of said spring structure to move said other end of said spring structure on said trip member and to move said spring structure to thereby change the line of action of said spring structure relative to said movable contact arm whereupon said spring structure operates to move said movable contact arm to an open position.

3. A circuit breaker comprising, a stationary contact, a movable contact, a movable contact arm carrying said movable contact and movable to open and close said contacts, a trip member having an elongated slot therein, a spring structure having a first end supported on said movable contact arm and a second end supported on said trip member within said slot, means operable automatically upon the occurrence of certain predetermined current conditions to release said trip member whereupon said spring structure operates to move said trip member to efiect movement of said movable contact arm to open said contacts, and said second end of said spring structure moving longitudinally within said slot to change the line of action of said spring structure during said automatic opening operation.

4. A circuit breaker comprising, in combination, a stationary contact, a movable contact arm comprising an upper part and a lower part, a movable contact supported on said lower part, said movable contact arm having a substantially straight center line and being movable to open and close said contacts, a trip member having a track thereon, a spring having a substantially straight center line and being connected under tension at one end on said movable contact arm and at the other end on said track, trip means latching said trip member and operating automatically upon the occurrence of an overload current above a predetermined value to release said trip member, said trip member when released moving under the force of said tensioned spring to move said other end of said spring between two spaced points on said track and to move said spring to thereby change the line of action of said spring relative to said movable contact arm whereupon said spring operates to move said movable contact arm to open said contacts, said centerlines meeting at a point when said contacts are closed, and when said contacts are closed the angle between said spring and said upper part of said movable contact arm and determined by said centerlines being an angle between 16 and 45 5. In a circuit breaker, a stationary contact, an elongated movable contact arm, a movable contact supported near one end and on one side of said movable contact arm, said movable contact arm being movable to open and close said contacts, an operating member operatively supporting the other end of said movable contact arm at a point A, a latched trip member, a spring structure connected at one end to said movable contact arm at a point B and at the other end to said latched trip member at a point C, said spring structure being disposed generally on said one side of said movable contact arm, when said contacts are in the closed position the angle between said points ABC being an angle between 16 and 45, said connection between said other end of said spring structure and said trip member being a slot-and-pin type of connection, means operable automatically upon the occurrence of certain abnormal current conditions to effect release of said latched trip member, when released said trip member moving under the force of said spring structure to move said other end of said spring structure on said trip member and to move said spring structure to change the line of action of said spring structure relative to said contact arm whereupon said spring structure operates to move said contact arm to an open position.

6. A circuit breaker comprising, in combination, a stationary contact, a movable contact, a movable contact arm carrying said movable contact and movable to open and close said contacts, a trip member pivotally supported at one end, trip means latching said other end of said trip member to maintain said trip member in a normal position, said trip member having an elongated opening therein, a spring structure supported under tension between said movable contact arm and said trip member, a first end of said spring structure being supported on said movable contact arm and a second end of said spring structure being supported on said trip member in said elongated opening at one end of said elongated opening, trip means operating automatically upon the occurrence of certain predetermined current values to unlatch said trip member, said trip member when unlatched moving under the force of said spring to effect movement of said second end of said spring structure from said one end of said elongated opening to the opposite end of said elongated opening to change the line of action of said spring structure relative to said movable contact arm whereupon said spring structure operates to move said movable contact arm to open said contacts.

7. A circuit breaker comprising, in combination, a stationary contact, a movable contact, a movable contact arm carrying said movable contact and movable to open and close said contacts, a latched trip member having an elongated slot therein, a spring structure having a first end supported on said movable contact arm and a second end supported on said trip member within said slot, means operable automatically upon the occurrence of certain abnormal conditions to release said trip member whereupon said spring structure operates to move said trip member during which movement said second end of said spring structure is moved within said slot to change the line of action of said spring structure whereupon said spring structure operates to move said movable contact arm to open said contacts, and roller means adapted to facilitate movement of said second end of said spring structure within said slot..

8. In a circuit breaker, a stationary contact, a movable contact, a movable contact arm carrying said movable contact and being movable to open and close said contacts, an operating member operatively connected to said movable contact arm, a trip member, a spring structure having one end connected to said movable contact arm and the other end connected to said trip member, said other end being movable between two spaced points on said trip member, a kicker member mounted for movement in proximity to said spring structure, said operating member being manually operable from an on position to an off position which movement moves said kicker member to effect movement of said other end of said spring structure relative to said trip member and which movement also moves said movable contact arm whereby the line of action of said spring structure is changed so that said spring structure operates to move said movable contact arm to open said contacts.

9. A circuit breaker comprising, in combination, relatively movable contacts, a movable current-carying contact arm having one of said contacts secured thereon, an operating member operatively supporting one end of said movable contact arm, a trip member having an elongated slot therein, means latching said trip member in a normal position, a spring structure connected at one end to said movable contact arm and at the other end to said trip member in said slot, said operating member being manually movable from an on position to an off position to change the line of action of said spring structure to effect opening of said contacts mounted for movement in proximity to said spring structure, a kicker member, during said manual operation said operating member engaging and moving said kicker member whereupon said kicker member engages said spring structure to move said other end of said spring structure in said slot to aid the said changing of the line of action of said spring structure.

10. In a circuit breaker, a stationary contact, a movable contact, a movable contact arm carrying said movable contact and being movable to open and close said contacts, an operating member operatively connected to said movable contact arm, a trip member having an elongated slot therein, trip means latching said trip member in a normal position, a spring structure having one end connected to said movable contact arm and the other end connected to said trip member in said slot, a kicker member mounted for movement in proximity to said spring structure, said operating member being manually movable from an on position to an off position during which movement said operating member engages and moves said kicker member to move said kicker member to thereby move said spring structure to effect longitudinal movement of said other end of said spring structure in said elongated slot and which operating-member movement also moves said movable contact arm where by the line of action of said spring structure is changed whereupon said spring structure operates to move said movable contact arm to open said contacts, said trip means being operable automatically upon the occurrence of certain abnormal current conditions to release said trip member, said trip member when released moving under the force of said spring structure to change the line of action of said spring structure whereupon said spring structure operates to open said contacts, and said other end of said spring structure moving longitudinally within said elongated slot during said automatic opening operation.

11. A circuit breaker comprising a stationary contact, a movable contact, a movable contact arm carrying said movable contact and being movable to open and close said contacts, an operating member operatively connected to said movable contact arm, a trip member having a slot therein, a spring structure having one end connected to said movable contact arm and the other end connected to said trip member in said slot, means latching said trip member in a normal position, a kicker member pivotally supported intermediate its ends on said trip member, said operating member being manually movable from an on position to an ofi position during which movement said operating member engages one end of said kicker member moving said kicker member so that the other end of said kicker member engages said spring structure to move said other end of said spring structure within said slot, and said movement of said operating member also moving said movable contact arm whereby the line of action of said spring structure is changed so that said spring structure operates to move said movable contact arm to open said contacts.

12. A circuit breaker comprising a stationary contact, a movable contact, a movable contact arm carrying said movable contact and being movable to open and close said contacts, an operating member operatively connected to said movable contact arm, a trip member having an elongated opening therein, a spring structure having one end connected to said movable contact arm and the other end connected to said trip member in said opening, means latching said trip member in a normal position, a kicker member pivotally supported intermediate its ends on said trip member, said operating member being manually movable from an on position to an off position during which movement said operating member engages one end of said kicker member pivotally moving said kicker member so that the other end of said kicker member engages said spring structure to move said other end of said spring structure longitudinally within said opening, and said movement of said operating member also moving said movable contact arm whereby the line of action of said spring structure is changed so that said spring structure operates to move said movable contact arm to open said contacts, said trip means operating automatically upon the occurrence of certain predetermined current values to release said trip member, said trip member when released moving under the force of said spring structure to change the line of action of said spring structure whereupon said spring structure operates to open said contacts, and said other end of said spring structure moving longitudinally within said opening during said automatic opening operation.

13. A circuit breaker comprising a stationary contact, a movable contact, a movable contact arm carrying said movable contact and being movable to open and close said contacts, an operating member operatively connected to said movable contact arm, a trip member having an elongated slot therein, a spring structure having one end connected to said movable contact arm and the other end connected to said trip member in said slot, means latching said trip member in a normal position, a kicker member pivotally supported intermediate its ends on said trip member, said operating member being manually movable from an on position to an off position during which movement said operating member engages one end of said kicker member pivoting said kicker member so that the other end of said kicker mem ber engages said spring structure to move said other end of said spring structure longitudinally within said slot, and said movement of said operating member also moving said movable contact arm whereby the line of action of said spring structure with respect to said movable contact arm is changed so that said spring structure operates to move said movable contact arm to open said contacts, said trip means operating automatically upon the occurrence of certain predetermined current values to release said trip member, said trip member when released moving under the force of said spring structure to change the line of action of said spring structure with respect to said movable contact arm whereupon said spring structure operates to move said movable contact arm to open said contacts, said other end of said spring structure moving longitudinally within said slot during said 1 1 1 2 automatic opening operation, and a roller member adapted 2,467,797 4/49 Wise 200-116 to facilitate movement of said other end of said spring 2,504,793 4/50 Baxter 200-116 structure within said slot. 2,844,674 7/58 Anderson 200-67 2,975,253 3/61 Nimylowycz 200116 References Cited by the Examiner 5 3,061,698 10/62 L 200-33 UNITED STATES PATENTS BERNARD A. GILHEANY, Primary Examiner.

2,416,170 2/47 Game et a1. 200-116 

1. A CIRCUIT BREAKER COMPRISING, IN COMBINATION, A STATIONARY CONTACT, A MOVABLE CONTACT, A MOVABLE CONTACT ARM CARRYING SAID MOVABLE CONTACT AND BEING MOVABLE TO OPEN AND CLOSE SAID CONTACTS, A TRIP MEMBER HAVING A TRACK THEREON, A SPRING STRUCTURE HAVING ONE END SUPPORTED ON SAID MOVABLE CONTACT ARM AND THE OTHER END SUPPORTED ON SAID TRACK, TRIP MEANS LATCHING SAID TRIP MEMBER AND OPERATING AUTOMATICALLY UPON THE OCCURRENCE OF OVERLOAD CURRENTS ABOVE A PREDETERMINED VALUE TO RELEASE SAID TRIP MEMBER, SAID TRIP MEMBER WHEN RELEASED MOVING TO EFFECT OPENING OF SAID CONTACTS, AND SAID SPRING STRUCTURE MOVING BETWEEN TWO SPACED POINTS ON SAID TRACK TO CHANGE TO LINE OF ACTION OF SAID SPRING STRUCTURE DURING SAID AUTOMATIC OPENING OPERATION. 